:root {
    --color-primary: #6699cc;
    --color-secondary: #4d7ba8;
    --color-accent: #ec6726;

    --color-text-subtle: #67717e; /* Optional/secondary content */
    --color-text-base: #575f6a; /* Standard body text */
    --color-text-strong: #39434d; /* Emphasized text */
    --color-text-heavy: #31363c; /* Headings */

    --color-background: #fafafa;
    --color-background-alt: #f5f5f5;
    --color-background-white: #ffffff;
    --color-border: #e5e5e5;

    --font-display: "Noto Serif", serif;
    --font-body: "Noto Sans", sans-serif;

    --max-width: 75rem;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    font-size: 1.125rem;
    line-height: 1.7;
    color: var(--color-text-base);
    background-color: var(--color-background);
}

/* Links */
a {
    color: var(--color-primary);
    text-decoration: none;
}

a:hover {
    color: var(--color-secondary);
    text-decoration: underline;
}

/* Focus states for accessibility */
a:focus-visible,
button:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Navigation */
.nav-bar {
    position: sticky;
    top: 0;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    z-index: 2;
    padding: 1rem 0;
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    height: 3.5rem;
}

.nav-logo img {
    height: 100%;
    width: auto;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    font-size: 1rem;
    color: var(--color-text-base);
    text-decoration: none;
    font-weight: 500;
    position: relative;
}

.nav-links a::after {
    content: "";
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-secondary);
    transition: width 0.3s ease;
}

.nav-links a:hover {
    color: var(--color-secondary);
    text-decoration: none;
}

.nav-links a:hover::after {
    width: 100%;
}

.nav-links a.active {
    color: var(--color-secondary);
}

.nav-links a.active::after {
    width: 100%;
}

/* Hamburger Menu Button */
.hamburger {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    z-index: 3;
}

.hamburger-line {
    display: block;
    width: 1.5rem;
    height: 2px;
    background-color: var(--color-text-heavy);
    margin: 0.25rem 0;
    transition: all 0.3s ease;
}

/* Hero Section */
.hero {
    position: relative;
    padding: 6rem 0 4rem;
    background: linear-gradient(135deg,
            var(--color-background) 0%,
            var(--color-background-alt) 100%);
}

.hero-content {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 4rem;
}

.hero-text {
    flex: 1;
}

.hero-graphic {
    flex: 0 0 25rem;
}

.hero-graphic img {
    width: 100%;
    height: auto;
}

.project-title {
    font-family: var(--font-display);
    margin-bottom: 1.5rem;
}

.title-main {
    display: block;
    font-size: 4.5rem;
    font-weight: 600;
    color: var(--color-primary);
    letter-spacing: 0.02em;
    line-height: 1.1;
}

.title-sub {
    display: block;
    font-size: 2.2rem;
    font-weight: 300;
    color: var(--color-text-heavy);
    margin-top: 0.5rem;
    letter-spacing: -0.01em;
}

.project-dates {
    font-size: 1.25rem;
    color: var(--color-primary);
    font-weight: 500;
    letter-spacing: 0.03em;
}

/* Main Content */
.section {
    padding: 2rem 2rem;
    max-width: var(--max-width);
    margin: 0 auto;
}

.section h2 {
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 600;
    color: var(--color-text-heavy);
    margin-bottom: 4rem;
    letter-spacing: -0.01em;
    position: relative;
    display: inline-block;
}

.section h2::after {
    content: "";
    position: absolute;
    bottom: -0.5rem;
    left: 0;
    width: 3.75rem;
    height: 3px;
    background-color: var(--color-primary);
}

.section h3 {
    font-family: var(--font-display);
    font-size: 1.6rem;
    font-weight: 600;
    color: var(--color-text-heavy);
    margin-bottom: 1rem;
}

.section h4 {
    font-family: var(--font-body);
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--color-text-heavy);
    margin-bottom: 0.5rem;
}

.section p+p {
    margin-top: 1.2rem;
}

.section-intro {
    font-size: 1.15rem;
    color: var(--color-text-subtle);
    margin-bottom: 2.5rem;
}

.text-columns {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
}

/* Work Packages */
.work-packages-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2.5rem;
}

.work-package {
    background-color: var(--color-background-white);
    padding: 2rem;
    border-radius: 0.5rem;
    border: 1px solid var(--color-border);
}

.lead-org {
    font-size: 1rem;
    color: var(--color-text-strong);
    font-weight: 600;
    margin-bottom: 1.5rem;
}

.work-package ul {
    list-style: none;
    padding: 0;
}

.work-package li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--color-border);
}

.work-package li:last-child {
    border-bottom: none;
}

.work-package li strong {
    color: var(--color-text-strong);
    font-weight: 600;
}

/* Partners */
.partner {
    margin-bottom: 3.5rem;
    padding-bottom: 3rem;
    border-bottom: 1px solid var(--color-border);
}

.partner:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.partner-header .partner-logo {
    height: auto;
    max-height: 5rem;
    max-width: 15rem;
    margin-bottom: 1.5rem;
}

.team-members {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1rem;
    margin-top: 1.5rem;
}

.team-member {
    padding: 1rem;
    background-color: var(--color-background-white);
    border-radius: 0.25rem;
    border: 1px solid var(--color-border);
    min-height: 6rem;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.member-name {
    font-weight: 600;
    color: var(--color-text-heavy);
}

.member-role {
    color: var(--color-text-subtle);
}

.member-link {
    margin-top: auto;
}

/* Advisory Board */
.advisory-list {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0;
}

.advisor {
    padding: 1rem 0;
    border-bottom: 1px solid var(--color-border);
    font-weight: 500;
    color: var(--color-text-base);
}

/* Data Sources */
.data-sources-list {
    margin-top: 2rem;
}

.data-source {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background-color: var(--color-background-white);
    border-left: 4px solid var(--color-accent);
    border-radius: 0.25rem;
}

.data-source-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 0.75rem;
}

.data-source-logo {
    height: 2.5rem;
    width: auto;
}

.data-source-header h4 {
    margin-bottom: 0;
}

.data-source h4 a {
    color: var(--color-primary);
    text-decoration: underline;
}

.data-source h4 a:hover {
    color: var(--color-secondary);
}

.data-source p {
    margin: 0;
    color: var(--color-text-subtle);
}

.data-source:last-child {
    margin-bottom: 0;
}

/* About */
.project-info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1rem;
}

.info-block {
    padding: 2rem;
    background-color: var(--color-background-white);
    border-radius: 0.5rem;
    border: 1px solid var(--color-border);
}

.info-block h4 {
    font-size: 1.1rem;
    margin-bottom: 1rem;
    color: var(--color-text-strong);
}

.info-block p {
    margin: 0;
}

.social-media-note {
    margin-top: 2rem;
    margin-bottom: 4rem;
    padding: 1.5rem;
    background-color: var(--color-background-white);
    border-left: 4px solid var(--color-accent);
    border-radius: 0.25rem;
}

.social-media-note p {
    margin: 0;
}

/* Footer */
.footer {
    background-color: var(--color-background-alt);
    border-top: 1px solid var(--color-border);
    color: var(--color-text-base);
    padding: 3rem 2rem;
}

.footer-content {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-funding {
    flex: 1;
}

.footer-logo {
    height: 2.5rem;
    width: auto;
    margin-top: 1rem;
}

.footer-legal {
    text-align: right;
}

/* Responsive Design */
@media (max-width: 62rem) {
    .hamburger {
        display: block;
    }

    .nav-links {
        position: fixed;
        top: 0;
        right: 0;
        width: 100%;
        max-width: 15rem;
        height: 100vh;
        background-color: var(--color-background-white);
        flex-direction: column;
        padding: 5rem 2rem 2rem;
        box-shadow: -2px 0 10px rgba(0, 0, 0, 0.1);
        visibility: hidden;
        opacity: 0;
        transition: visibility 0s 0.3s, opacity 0.3s ease;
        z-index: 2;
        overflow-y: auto;
    }

    .nav-links.active {
        visibility: visible;
        opacity: 1;
        transition: visibility 0s, opacity 0.3s ease;
    }

    .nav-links a {
        font-size: 1rem;
        padding: 1rem 0;
        border-bottom: 1px solid var(--color-border);
    }

    .nav-links a:last-child {
        border-bottom: none;
    }

    .nav-logo {
        height: 2.5rem;
    }

    .nav-container,
    .hero-content {
        padding-left: 1.5rem;
        padding-right: 1.5rem;
    }

    .hero {
        padding: 4rem 0 3rem;
    }

    .hero-content {
        flex-direction: column;
        gap: 2rem;
    }

    .hero-graphic {
        width: 100%;
        max-width: 25rem;
        flex: none;
    }

    .title-main {
        font-size: 3rem;
    }

    .title-sub {
        font-size: 1.6rem;
    }

    .text-columns,
    .work-packages-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .section {
        padding: 3rem 0;
    }

    .section>* {
        padding-left: 1.5rem;
        padding-right: 1.5rem;
    }

    .section h2::after {
        left: 1.5rem;
    }

    .social-media-note {
        margin-left: 1.5rem;
        margin-right: 1.5rem;
    }

    .advisory-list {
        grid-template-columns: 1fr;
    }

    .footer {
        padding: 3rem 1.5rem 2rem;
    }

    .footer-content {
        flex-direction: column;
        gap: 3rem;
        text-align: center;
    }

    .footer-legal {
        text-align: center;
    }

    .section h2 {
        font-size: 2rem;
    }
}

@media (max-width: 36rem) {
    .title-main {
        font-size: 2.5rem;
    }

    .title-sub {
        font-size: 1.3rem;
    }

    .footer-logo {
        height: 2rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    * {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
}